Ethers of chlorinated and fluorinated phenols



United States Patent ETHERS OF CHLORINATED AND FLUORINATED PHENOLSWilliam L. Howard, Stanley R. McLane, Jr., and Robert Weintraub,Frederick, Md.

No Drawing. Application October 29, 1954 Serial No. 465,765

17 Claims. (Cl. 260-612) (Granted under Title 35, U. S. Code (1952),see. 266) The invention described herein may be manufactured and used byor for the Government of the United States of America for governmentalpurposes without the payment to us of any royalty thereon.

This invention relates to the control of plant growth by long-chainaliphatic ethers of chlorinated and fluorinated phenols. It also relatesto certain new compounds in this group. i

We have found that certain halogenated phenyl alkyl ethers are effectiveas plant growth regulators, functioning as herbicides and also in theproduction of sterility. They may also be employed to prevent prematuredrop of fruit.

The ethers which we have found to be effective have straight alkylchains containing even numbers of carbon atoms. They are furthercharacterized as follows:

Phenolic group:

p Aliphatic chain, carbon atoms 4-chlorophenyl Of these compounds, thegroup consisting of 4-chlorophenyl myristyl ether, 2,4dichlorophenylmyristyl ether and 2,4-dichlorophenyl cetyl ether have outstandingactivity. 2,4dichlorophenyl myristyl ether is the mostactive of all.

in comparison to the well known herbicide 2,4.-dichloropheuoxy aceticacid (2,4--D), these compounds possess distinctive properties in thatthey give a delayed action which is spread over along period of time,giving a greater over all effect when used in herbicidal quantities.When used in sub-lethal quantities the action, as in production ofseedless fruit, is more gradual and produces fewer objectionable sideefifects. As herbicides, the ethers are applied in the same manner as,but are less active than 2,4-D. Due to their low solubility in water,they are preferably emulsified by the use of suitable emulsifyingagents. Since they have densities near that of water they produce stableemulsions. They may also be used as solutions in alcohols, glycolethers, etc. Other growth regulating properties are illustrated by thefollowing experiments EXAMPLE I Field grown tomato, pepper, squash, andeggplant plants were sprayed with 2,4 dichlorophenyl tetradecyl ether atrates of 0.1 and 0.5 pound per acre. Seedless fruit was produced in eachcase. The seedless tomatoes were quite firm and were not as puffy assome seedless fruit. Tomato yields were not reduced. The eggplant wasnormal both in form and in yield. Pepper yields were not reduced but thefruit was flattened and not of normal shape. Squash was of abnormalshape.

2,839,582 Patented June 17, 1958 2 EXAMPLE II Setaria italica wassprayed with 4-chlorphenyl dodecyl ether and 4-chlorophenyl tetradecylether at the rate of 1 pound per acre, producing sterility. Thissuggests the use of these ethers for reducing the amount of seedproduced by foxtail and giant foxtail, both of which are Setariaspecies, as a means of controlling the spread of these weeds.

Of the compounds which we have found to be useful, a considerable numberare new and our invention also embraces these new compounds. These novelcompounds are the alkyl ethers of 2,4-dichlo-rophenol having an evennumber of carbon atoms in a straight alkyl chain containing from eightto eighteen carbon atoms, 2,4,5- trichlorophenyl n-hexadecyl ether,4-fluorophenyl n-dodecyl ether, 4-fluorophenyl n-tetradecyl ether,2,4-difluorophenyl n-dodecyl ether, and the n-dodecyl, n-tetradecyl, andn-hexadecyl ethers of 2-methyl-4-i lu orophenol. The new ethers. areoils or crystalline solids somewhat soluble in many organic solventssuch as hydrocarbons, alcohols, ethers, ketones, etc., and practicallyinsoluble in water. They are stable to light, air, and carbon dioxide,and have low volatilities. They areuseful in the control of the growthof plants, as described above, and as intermediates in the preparationof more complex organic derivatives.

The compounds may be prepared by reacting (1) at least a molecularproportion of the proper chlorinated or fluorinated phenol as the sodiumsalt thereof, and (2) a molecular proportion of an alkyl halide such asoctyl chloride, myristyl bromide, cetyl bromide, etc., or any similarhalogenated derivative of an alkane bearing the desired alkyl groupcarbon atoms. The reaction is carried, out in the presence of a solventsuch as absolute ethanol. A catalyst such as sodium or potassium iodidemay be used to facilitate halogen interchange and increase the yield ofthe ether by preventing dehydrohalogcnation of the alkyl halide to thecorresponding alkene.

In the preferred method of preparation, the sodium is dissolved inabsolute ethanol and an equivalent amount of the phenol is added to formthe sodium phenolate. Potassium iodide is then added and dissolved,followed by an equimolecular amount of the alkyl halide. The mixture isthen refluxed for 12 hours or longer. The reaction mixture is dilutedwith water and the ether separates out. The aqueous-alcoholic layer isextracted with a suitable solvent, the extract combined with theprecipitated ether and the resulting solution washed with aqueous alkalito remove unreacted phenol and then with water to remove residual saltsand alkali. After drying the extract, the solvent is evaporated, leavingbehind a liquid or solid other which can be purified by distillation atreduced pressure or recrystallized from a suitable medium, as dictatedby its physical properties.

As an illustration of the method of preparation, the production ofmyristyl 2,4-dichlorophenyl ether will be described. As has beenpreviously pointed out, this compound is the most active for ourpurposes of all of the compounds of our group. The other ethers areprepared in a similar manner.

EXAMPLE III 10.2 grams of 2,4-dichlorophenol was dissolved in 20milliliters of absolute ethanol. To this was added a solution of 1.4grams of sodium metal dissolved in 60 milliliters of absolute ethanol. Asolution of 9.0 grams of potassium iodide in milliliters of absoluteethanol was added and the mixture refluxed 15 minutes. 20 grams ofmyristyl bromide was then added and the resulting mixture refluxed 36hours on a steam bath.

After cooling the reaction mixture it was diluted with 500 millilitersof water, then extracted with 300 mil- 3. liliters of ethyl ether in 100milliliter portions. The ether extract was separated and Washed With 100milliliters of sodium hydroxide solution, then 300 milliliters of water,again separated and dried over anhy- 4 n-Octyl 2,4-dichlorophenyl ether.n-Decyl 2,4-dichloropheny1 ether. Lauryl 2,4-dichlorophenyl ether.Myristyl 2,4-dichlorophenyl ether.

oetadecyl bromide cetyl bromide lauryl bromide.

do 2,4,5 trichlorophenol. 4 fiugrophenol cetyl bromide octadccyl 2,4dichlorophenyl ether cetyl 2,4,5 triehlorophenyl ether lauryl 4fluorophenyl ether myristyl bromide. myristyl 4 fluorophenyl ether cetylbromide cetyl 4 fluorophenyl etherlauryl bromide lauryl 2,4difiuorophenyl ethermyristyl bromide. myrsityl 2,4 difluorophenyl ether.cetyl bromide eetyl 2,4 difluorophonyl ether lauryl bromide. lauryl 2methyl 4 fluorophenyl ether... myristyl bromide. myristyl 2 methyl 4flluorophenyl ethe eetyl 2 methyl 4 fluorophenyl ether drous sodiumsulfate. 5 Cetyl 2,4-dichloropheny1 ether.

The ethyl ether Was removed by distillation leaving Cetyl2,4,5-trichlorophenyl ether. behind a solid which was crystallized fromany suitable Lauryl 4-fluorophenyl ether.

solvent, such as ether or ligro'ine giving White crystals of 10.Myristyl 4-fluorophenyl ether. 2,4-dichlorophenyl myristyl ether meltingat 33-34 C., 11. Cetyl 4-fiuorophenyl ether. and having carbon andhydrogen contents of 66.56% and 12. Lauryl 2,4-difluorophenyl ether.

8.85% respectively. For C I-I Cl O the theoretical 13. Myristyl2,4-difluorophenyl ether. values are 66.84% and 8.98% respectively. 14.Cetyl 2,4-difiuorophenyl ether.

Representative ethers of our group that have been pre- 15. Lauryl2-methyl-4-fluorophenyl ether. pared by the method described above, andthe reactants 16. Myristyl 2-methyl-4-fluorophenyl ether. employed, areshown in Table I. 15 17. Cetyl 2-methyl-4-fluorophenyl ether.

Table I Reactants Boiling Point Melting Ether Product Point, [nlnDensity O. Temp., Pressure, 0. Alkyl Halide Phenol O. mm. Hg

abs.

1: octyl bromide 2,4 diehlorophenol n octyl 2,4 dichlorophenyl ether ndecyl bromide do n decyl 2,4 dichlorophenyl ether.. lauryl bromide dolauryl 2,4 diehlorophenyl ethermyristyl bromide do my1-isty12,4dichlorophenyl eth cetylbromidenn do eet v12,4diehlorophenylethen-..

While we have described our compounds, their propstood that a number ofvariations are possible. We therefore desire our invention to be limitedsolely by the scope of the appended claims.

We claim:

1. A chemical compound possessing biological activity selected from thegroup consisting of: alkyl ethers of 2,4- dichlor'ophenol having an evennumber of carbon atoms in the range 8 to 18 in a straight chain in thealkyl group; the n-hexadecyl ether of 2,4,5-trichlorophenol, thendodecyl, n-tetradecyl and n-hexadecyl ethers of i -fluorophenol, then-dodecyl, n-tetradecyl and n-hexadecyl ethers of 2,4-difluorophenol andthe n-dodecyl, n-tetradecyl and n-hexadecyl ethers of2-methyl-4-fluorophenol.

' 2. An alkyl ether of 2,4-dichloropheno1 having in the alkyl group aneven number of carbon atoms in the range of 8 to 18 in a straight chain.

References Cited in the file of this patent UNITED STATES PATENTS2,054,509 Pastac Sept. 15, 1936 40 2,137,784 Prutton et al. Nov. 22,1938 2,188,734 CarsWel1 Jan. 30, 1940 2,327,338 Carswell Aug. 24, 19432,581,972 Rottschaefer Ian. 8, 1952 2,594,935 Ladd et al. Apr. 29, 1952OTHER REFERENCES Jones: Journal, Chemical Society (London), 1935, pp.1831-5.

McLane et al.: Weeds, vol. II, October 1953, No. 4,

1. A CHEMICAL COMPOUND POSSESSING BIOLOGICAL ACTIVITY SELECTED FROM THEGROUP CONSISTING OF: ALKYL ETHERS OF 2,4DICHLOROPHENOL HAVING AN EVENNUMBER OF CARBON ATOMS IN THE RANGE 8 TO 18 IN A STRAIGHT CHAIN IN THEALKYL GROUP; THE N-HEXADECYL ETHER OF 2,4,5-TRICHLOROPHENOL, THENDODECYL, N-TETRADECYL AND N-HEXADECYL ETHERS OF 4-FLUOROPHENOL, THEN-DODECYL, N-TETRADECYL AND N-HEXADECYL ETHERS OF 2,4-DIFLUOROPHENOL ANDTHE N-DODECYL, N-TETRADECYL AND N-HEXADECYL ETHERS OF2-METHY-4-FLUOROPHENOL.